The electronic device fabrication industry requires various chemicals as raw materials or precursors to fabricate integrated circuits and other electronic devices. Deposition processes such as, chemical vapor deposition (CVD) and atomic layer deposition (ALD) processes, are used in one or more steps during the manufacture of a semiconductor device to form one or more films or coatings on the surface of a substrate. In a typical CVD or ALD process, a precursor source that may be in a solid and/or liquid phase is conveyed to a reaction chamber having one of more substrates contained therein where the precursor reacts under certain conditions such as temperature or pressure to form the coating or film on the substrate surface.
There are several accepted technologies to supply a precursor vapor to a processing chamber. One process supplies the liquid precursor to a processing chamber in a liquid form with the flow rate controlled by a liquid mass flow controller (LMFC) and then the precursor is evaporated by a vaporizer at the point of use. A second process involves a liquid precursor being evaporated by heating and the resulting vapor is supplied to a chamber with the flow rate controlled by a mass flow controller (MFC). A third process involves bubbling a carrier gas upwardly through the liquid precursor. A fourth process involves enabling the carrier gas to flow over the surface of the precursor contained in a canister and carrying precursor vapor out of the canister and subsequently to the process tool.
Described herein are containers, systems and methods using same for delivering high purity process chemical precursors to a process tool that is used in the manufacture of a semiconductor device. More specifically, described herein are systems comprising a container (a vessel or an ampoule) with flow distributor, such as multiple small holes or jets; and chemical precursors for a process tool such as a deposition reactor in a chemical vapor deposition (CVD) or atomic layer deposition (ALD) process.
The delivery of chemical vapor from a solid precursor by sublimation, is one of the subject matters of the present invention
One challenge associated with conventional containers that deliver chemical vapor from a solid precursor by sublimation is difficulty in obtaining high utilization of precursor. It is difficult to minimize the amount of precursor left in the container when it is taken out of service to be cleaned and refilled. One cause of this problem is that, in conventional solid source containers, the distance between the surface of the precursor and the inlet and outlets used to circulate the carrier gas, as well as the volume of the area in which the carrier gas contacts the precursor vapor, increases as the precursor is exhausted.
Attempts have been made to increase precursor utilization, including more uniform heating of the precursor chamber and improved carrier gas circulation. Although these efforts have resulted in improvements in precursor utilization, the structures needed to implement these improvements can make the containers more difficult to clean and there is a need for further improvement in the precursor utilization.
Some prior arts provide the designs where the inlet tube is positioned above the precursor surface but don't provide sufficient momentum for carrier gas to perturb the surface of the precursor at low container fill level or at low load level. Thus, precursor delivery rate for prior art designs is typically significantly lower at low container fill level (or at low load level) compare to precursor delivery rate at high container fill level (or at high load level).
Some prior arts also provide the designs where the inlet tube positioned below the precursor surface. Precursors (liquid or solid) are supplied in bubblers. Wherein in use, a carrier gas is bubbled through and becomes saturated with the precursor via a dip pipe, as disclosed in U.S. Pat. Nos. 8,313,804 B, 2, 6,698,728 and 6,033,479 A.
However, these designs often present problems for delivery of solid precursors due to plugging inlet with solids, non-uniform delivery rate due to carrier gas channeling around the solids, and delivery rate variation during container utilization.
Thus, there is a need in the art for a system and a method for delivery of precursors to a deposition or process site that aiming to overcome the abovementioned drawbacks.